1. Field of the Invention
The present invention relates generally to valves and, more particularly, to a modular rotary selector valve for selecting amongst a plurality of individual source lines to divert the contents of a selected source line to a selected destination.
2. Description of the Related Art
Although multiple port selector valves have, in the past, been used in a variety of applications, a predominant use of such valves has been in the area of oil and natural gas production. Broadly speaking, oil and gas development entails the drilling of wells, bringing underground well fluids to the surface (i.e., production), and preparing the obtained oil-gas mixture for refining. Because many oil fields contain a number of producing wells at any given time and such wells may be spaced a great distance apart, it is generally most efficient to transport the production from each of the individual wells to a central gathering station so that the well fluids can be combined and then transferred to subsequent stages in the production process where the oil and gas will be separated prior to refining.
To properly manage the production portion of this process it is important to acquire accurate and immediate test data from each of the individual producing wells in the field. The progress of the water front, steam front or pressure front, and the maintenance of proper injection conditions are all carefully controlled and timed. To accomplish this, each well is tested individually by taking a test flow from each well's production line. This, of course, is done before the well fluids and gases from all of the wells are intermingled.
Since each of the wells' fluids and gases remain separate up to the central gathering station where they are all combined, rotary selector valves have been employed at the central gathering station whereby the required test flow is taken at this stage of the production process, rather than from each well individually. Such rotary selector valves selectively choose a single well production line from the plurality of well production lines for downstream testing. This saves on the amount of pipe necessary to implement the testing of individual wells and simplifies the overall testing process.
Existing rotary selector valves have a singular molded valve body with up to eight inlet ports for receiving the production from up to eight individual wells. The interior of the valve body is enclosed by a cover plate that mounts to the top of the valve body. Within the interior of the valve body is a rotor assembly that is rotatably mounted between the cover plate and the bottom of the valve body. The rotor assembly contains a single inlet opening and can be rotated so that the inlet opening isolates a single selected inlet port on the valve body to receive the well fluids from the production line coupled to the selected inlet port. The well fluids from the isolated inlet port are then directed through the rotor assembly to a test outlet at the bottom of the valve body. The well fluids received from the non-isolated inlet ports are combined within the interior of the valve body and exhausted through a production outlet, also at the bottom of the valve body.
Although such existing rotary selector valves operate in generally satisfactory fashion to select individual production lines for testing, such systems have inherent practical limitations. One such limitation is the size and total number of well production lines that can reasonably be accommodated using a single rotary selector valve. In order to provide for a greater number of inlet ports on the existing rotary selector valve design, the inside diameter of the valve body would have to be expanded as the size and number of inlet ports is increased. In addition, the valve body and pressure containing components of the rotary selector valve would have to be made of thicker or higher strength material to allow for increased operating loads encountered as a result of the larger physical size. These considerations would necessarily add to the bulk, weight, and cost of the rotary selector valve. Moreover, it would become physically and economically impractical to make a one-piece valve casting to accommodate a greater size or number of inlet ports.
Another limitation of the prior art valve design is that it does not offer the flexibility of being upgradable. If the user wishes to increase the number of inlet ports, change the size of the inlet or outlet ports, or change the inlet or outlet port connector types, the user would have to purchase an entirely new rotary selector valve. This is economically disadvantageous.
The present invention is directed at overcoming, or at least minimizing, one or more of the problems set forth above.